It’s a battle as old as the moment that Chevrolet decided it needed an answer to Ford’s pioneering pony car. The Mustang was a raging sales success and the Camaro looked to get a piece of the action. This week that classic battle takes the form of an online auction that pits Mustang listings against those of its Brand X competitor.

On Friday, Speed Digital joins forces with Hemmings and Proxibid to host its first in a series of monthly themed auctions, kicking things off in style with Mustangs vs. Camaros. The idea is to let the free market decide which marque is truly the most popular.

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Among the wide array of Mustangs up for sale are a 2017 Petty's Garage King Premier Edition Mustang, which will be auctioned with no reserve at 7 p.m. during the live auction with proceeds benefiting charity. Some of the other significant cars include a 1968 Shelby GT500KR convertible, a triple-black 1995 Mustang Cobra convertible, and a one-of-157, 5,500-mile 2011 Shelby GT350.

“We look forward to bringing this unique auction format to millions of Mustang and Camaro fans,” Neil Pitt, president of Speed Digital, said. “It will be exciting to see which fanbase has a stronger showing. Will a Mustang or Camaro bring in the highest winning bid? Will more Mustangs find new homes or will it be Camaros? Only time will tell, but it will be fun to watch it all unfold on May 26th.”

If you are in the market for a car and you want to help push the Mustang over the top, you can check out the cars up for auction right here, but don’t hesitate, as the Mustang vs. Camaro auction crosses the finish line at 8 p.m. EST on Friday.